<zoology> One of the barbs of the hypoptilum, or aftershaft of a feather. See Feather. ... (04 Mar 1998) ... Found on http://www.encyclo.co.uk/local/20973
Hy`po·ra'di·us noun ; plural Hyporadii . [ Prefix hypo- + radius .] (Zoology) One of the barbs of the hypoptilum, or aftershaft of a feather. See Feather . Found on http://www.encyclo.co.uk/webster/H/84